1. Field
The present disclosure relates to the field of multicarrier optical fiber communication technologies, and in particular to a method for estimating channel power, a method for monitoring a frequency spectrum characteristic, an apparatus and a system.
2. Description of the Related Art
In a multicarrier optical fiber communication system, subcarrier data are modulated in several optical carriers independent of each other, and a receiver receives and demodulates the subcarrier data respectively. Under an ideal condition, power of each subcarrier channel is stable, and a central channel received by a single receiver is less affected by neighboring channels. However, in a practical system, on the one hand, as wavelength and power of a laser are influenced by variation of driving currents, temperature fluctuation, and resonant cavity aging, etc., output carrier wavelength and power will drift in a certain range; and on the other hand, when multicarrier signals pass through the transmission system, the gains of the subcarrier channels are not completely identical, which results in power of the subcarriers are inconsistent. Such indefinite variation of power brings about relatively large influence to the multicarrier optical communication system, which is mainly embodied in: 1) as the power of the neighboring channels are over large, neighboring channel crosstalk occurs in the central channel in demodulation; and 2) power imbalance results in relatively large errors in system monitoring amount, such as subcarrier interval monitoring amount, and optical signal to noise ratio monitoring amount, etc.
It should be noted that the above description of the background is merely provided for clear and complete explanation of the present disclosure and for easy understanding by those skilled in the art. And it should not be understood that the above technical solution is known to those skilled in the art as it is described in the background of the present disclosure.